Now of course, I’m only operating on a theory, but I think the stars are aligning for one ending in particular for Dexter Morgan.
He’s going to wind up on his own kill table.
But first, a few things are going to happen. LaGuerta is going to continue to pursue the Bay Harbor Butcher and her theory that he’s someone who works for Miami Metro. I thought for a moment she might come to the conclusion it was Quinn as he fits the general profile of single white male, but he’s too much of a screw-up, whereas the Butcher has to be someone who is orderly.
The rest of this season will play out with Deb deciding to take matters into her own hand and kill Dexter’s girlfriend, putting him in the position of either following his code and killing Deb or letting her live, which would destroy the code. Of course, Dexter can’t kill his sister, so Dexter will be left to reinterpret the code, meaning he can kill more than just other killers and he will slip into this area in the final season. But not before Isaak Sirko has to be dealt with. Dexter doesn’t want to kill him because Sirko’s death will bring a lot more problems than it would solve. I’m not entirely certain how that gets fixed–perhaps Deb kills him on a legit shoot. On second thought, Quinn is going to kill him and go to prison.
But the final season will have LaGuerta zeroing in on Dexter as the Bay Harbor Butcher and I think they will go back to the books for source material and have a serial killer imitating Dexter’s M.O., killing those who have escaped justice, but maybe leaving more of a mess than Dexter would. Dexter and his sister will be on opposite sides, as she knows what he does and no longer finds issue with it, but also knows she has broken his code. After Dexter kills and disposes of his copycat, the noose will be tighter than ever, leaving Dexter and Deb on a final collision course where she winds up confronting him after he has strapped himself on a table and leaves her with no other choice but to kill him, freeing him and thus, saving herself. Because if Dexter isn’t the Butcher then Deb couldn’t have been covering for him.
I’m sure there are bugs in this theory. For instance, if the copycat is killing killers, then they should suspect Dexter of being a killer, right? Well, perhaps people already do. His wife’s killer was never caught and there had to be people who thought he had something to do with that.